1. In collaboration with Drs. Griffith and Friedman of the NIDCD, and Dr. Moore and Ms. Ferguson of the Institute for Hearing Research (Nottingham, England) the Audiology Unit is using a series of non-speech tests to evaluate sensory/temporal aspects of auditory processing. These tests are administered to twins attending an annual twins festival in an effort to determine heritability of auditory processing skills. We have previously identified heritability of speech-based auditory processing skills and are extending our research to evaluation of non-speech based skills. 2. In collaboration with the Molecular Biology and Genetics section, the Audiology Unit performs auditory and vestibular phenotypic assessments of individuals with hearing loss and enlarged vestibular aqueducts (EVA), as well as their siblings and parents. Over 90 probands and their families have now been ascertained. The audiology unit continues to evaluatie details of the auditory phenotype to search for features that predict genotype, clinical prognosis, or clinical diagnosis.&#8232;&#8232; 3. In collaboration with Drs Friedman and Griffith of the NIDCD and Dr Tsilou of the NEI, the Audiology Unit continues to evaluate auditory and balance function in persons with Usher Syndrome. We are interested in postural balance skills and their relationship to vestibular and visual function, type of Usher syndrome, and the progression of these skills over time. 4. In collaboration with investigators from other NIH institutes, we continue to evaluate auditory manifestations in neurofibromatosis type I (Widemann, NCI), Niemann Pick type C and Smith-Lemli Opitz Syndrome (Dr. Porter, NICHD), neonatal onset multi-system inflammatory disorder, familial cold urticaria, and Muckle-Wells syndrome (Dr. Goldbach-Mansky, NIAMS), Fanconi anemia and other inherited bone marrow failure syndromes (Dr. Alter, NCI), xeroderma pigmentosum (Dr. Kraemer, NCI), McCune-Albright syndrome and polyostotic fibrous dysplasia (Dr. Collins, NIDCR), von Hippel-Lindau disease (Lonser, NINDS). Smith-Magenis syndrome (Ms. Smith, NHGRI) and osteogenesis imperfecta (Marini, NICHD). We are interested in the auditory phenotype, natural history of hearing, and relationships to other aspects of disease/disorder and genotype. 5. In collaboration with investigators from other NIH institutes, we are evaluating hearing, electophysiologic auditory function, and central auditory processing manifestations in persons with WAGR syndrome (Dr. Han, NICHD), oculocutaneous albinism (Dr. Adams, NHGRI) and holoproencephaly (Dr. Muenke, NHGRI). We are interested in the auditory phenotype, including processing of dichotic and other complex sounds, and relationships to other aspects of the disease/disorder and genotype. 6. . In collaboration with investigators from other NIH institutes, the Audiology Unit is evaluating hearing, electrophysiologic auditory function, vestibular function, and postural balance in persons with neurofibromatosis type 2 (Drs. Asthagiri and Lonser, NINDS). We are interested in sensitivity of these assessments in early detection and monitoring of vestibular schwannomas. 7. In collaboration with investigators from other NIH institutes, we continue to implement and analyze studies of the auditory and/or vestibular system of persons participating in clinical trials in which the auditory and/or vestibular system may be at risk. These clinical trials include immunotherapy for melanoma (Dr. Rosenberg, NCI) and radiation therapy for brain tumors (Dr. Warren, NCI). We are interested in early identification of auditory/vestibular dysfunction, and management/prevention of auditory and/or vestibular dysfunction.